Vol. 15—1961 - NorthEastern Weed Science Society

247.
Weed Control in Soybeans with DNBPOver a Five-Year Period 1/
F. B. Springe~) Jr., H. w. IndI;' R. H. Cole and
C. D. Kesler _
Procedure
. ',;
:.,; For th.' five,..yearpe~tod, 1956· .1960,. DNBP1I'(am1ne salt
of dinitro~ortho.secondary"butyl.phellol) ';has been evaluated
a pre-e.rgence· tt"eaa.at 1n ~coatrol1ing weeds in soybeans at
~o loeations iIlD.laware.·' The soil type at the Newark.locationwas
•. Matapeake silt loam, and.at, ~the-,Georgetown' location,
a Norfolk:sandyloam.· 'lhe''Plot aiae.was eighteen feet long
with four rows, three fe~t apart. The c:hem1cal·was applied as
<
a pre-emergence spray at the 3 lbs./A. and 6 lbs./A. rate on
th~,.d_y of or; day follewlng planting. ':Weed control ratings
were .~"el) approxima.cel)', five "eeka after planting and all
receiv~d one ot .._0cultivations following the' weed ratings.
plots
The'broadleaf weed population at the experimental locations
'! 'consisted of rough pigweed (A1Daranthus retroflexus), cOlllDOnragweed
(Ambrosia artemisiifolia), lamb's quarter (Chenopodium
,1bum), and annual morning glory (Ipomoea purpurea). Grass
weed population consisted of yellow foxtail:· (Setaria lu~e8cens),
crabgrass (Digltaria sangUinalis), and yellownutgra8s (eYPerus
'-- esculentus). These same weeds cause the most' trouble 1n soybeans
for Delaware farmers and often become a serious problem.
Whe~~ ..• evere ·we,4infestat·ion. c8Q1lot be cont~blled :'bycultural
methods the ".eof:chemicals may be profitable. Chemical weed
control in soybeans is desirable for the following reasons:
to increase yields; to mak~.:e'31't~vation easier; to allow harvesting
of beans when mature; and to help eliminate
certified £leld8~' ' . "
weeds in
as
. r
Tl;a.eresults;of the;pastftve years lndicatesatisfactory
resultawith llHlf.Tbe'·effec:tiveoess .of DNBP·wasoutstanding
,.OS all the "herbicides, eva lua t.d 'at ,'the .two locations.
At the six pound rate, excellent. CORtrol ofi·weed growth,'
particularly rough pigweed, ragweed, and lamb's quarter, was
obtained without any harmful effects on yield. The higher rate
----~------------~
1/ Assistant Agronomist, Assistant Professor (presently Associate
Extension Specialist, Rutgers University), Assistant
Professor and Research Assistant, University of Delaware.
1/ DNBP.applied as Premerge, courtesy of the Dow Chemical Co.,
Midland, Michigan.
1/ Misc. Paper No. 373, Del. Agr. Exp. Sta.